Data transmission and communications, particularly high speed data communications, is a general field of interest that is widely studied. For example, both electrical and optical mediums, such as optical fibers, have been known approaches in data transmission and communication networks.
In one example of a communications network 1 shown in FIG. 1, a network such as a fiber optic network based on a passive star coupler is an example of a broadcast and select communication network architecture. A signal from a source node N is available to all other sink nodes S/N attached to the network. A sink node S/N has access to all signals placed onto the network. For a sink node to receive signals from one or multiple source nodes N at the same time, the sink node S/N must be enabled to receive the appropriate signals.
In the example of fiber optic communications, wavelength-division multiplexing (WDM) is a known technology which multiplexes multiple optical carrier signals on a single optical fiber by using different wavelengths (colors) of laser light to carry different signals. The term wavelength-division multiplexing is commonly applied to an optical carrier, which is typically described by its wavelength. In a wavelength-division multiplexing (WDM) broadcast and select architecture, many transmission channels are employed where each receiving node would typically need a photonic receiver and a serializer/deserializer (SERDES) for every WDM transmission channel on the fiber optic network. A SERDES is generally known and commonly used in high speed communications to convert data between serial data and parallel data interfaces in each direction. Thus, many SERDES are typically employed to receive all of the wavelengths in a WDM broadcast.
In many cases, however, a receiving or sink node would not be interested in all of the channels all of the time. FIG. 2 shows an example of the problem encountered in photonic deserialization activation in a typical fiber optic network FON configuration. As shown, the fiber optic network FON includes one or more source nodes (see Source Nodes A, B) that each include a processor, SERDES, and transmitter TX that transmit data through optical fibers to one or more sink nodes (see Sink Nodes C, D). Many designs require photonic receivers RX and the many SERDES (see Sink Nodes C, D) to remain powered constantly in order to be enabled so that processors can receive the data (e.g. wavelengths) transmitted by the source nodes (see Source Nodes A, B). It is known that high speed SERDES consume a significant amount of power. For example, a high speed photonic receiver and SERDES are estimated to consume approximately 0.5 Watts per channel received. Being able to temporarily shut down a SERDES or leave a SERDES powered down until it needs to be enabled would provide a significant power savings.
Previous designs to address this issue have been:
1. Use of a network controller that monitors all transmissions and communicates with each receiving node through a command channel to indicate when the receiving nodes should turn on which channels. This method, however, can consume significant resources (e.g. space, processing, bandwidth), and can require additional equipment, can experience loss of architecture flexibility, may not save power, and can introduce a single point of failure which could take down the entire network.
2. Use of a low speed signal embedded on top of a data transmission. Typical receiving nodes are designed to remove such low speed signals or slow transients to improve the high speed channel performance. Such a method requires adding a second modulation to the transmitting node which increases complexity of the network design.
3. Shutting down the transmitter and restarting. Such an approach can significantly interrupt other sink nodes receiving information on their channel(s).
4. Enable a receiving node so that its receive channel(s) are on a fixed schedule. This approach may save power, however, instances where SERDES should be activated may be missed. Power also would be wasted whenever the channel(s) are not needed, which could occur over extended periods of time.
Despite existing technology, devices and methods relating to enabling and disabling power consuming components, such as receiving nodes generally and SERDES channels in fiber optic networks can be further improved. Particularly, improvements are desired for increasing efficient use of power by such power consuming components.